Ultrawide Photonic Bandgap and Ultrastrong Photonic Localization Produced by Series of Periodic Networks

A series of periodic networks is designed, in which all of the unit cells construct a series of fractal triangles, and their extraordinary optical characteristics for producing ultrawide photonic bandgap (PBG) and ultrastrong photonic localization are investigated. The results indicate that with increasing fractal generation, the number of equivalent triangular loops increases exponentially, and consequently the gap-midgap ratio of the PBG produced by the networks with the integer waveguide length ratio of 1:2 enlarges rapidly and tends to the limit at 200%. For the networks with the noninteger waveguide length ratio of 1:2 +/-Delta d (where 0

Automated summary

The study found that with an increasing fractal generation, the number of equivalent triangular loops in the network exponentially increases, leading to a rapid enlargement of the gap-midgap ratio of PBG, approaching a limit of 200% for networks with an integer waveguide length ratio of 1:2. For networks with a non-integer waveguide length ratio of 1:2 +/- Delta d, the gap-midgap ratio of PBG varies with increasing Delta d.